WASHINGTON — The Trump administration on Monday hailed a Pennsylvania-based company’s deal to supply coal to Ukraine in preparation for winter heating needs, saying it would bolster a key U.S. ally often threatened by Russia.

The deal, potentially worth about $79 million, calls for Xcoal Energy and Resources to ship 700,000 tons of thermal coal to Ukraine to heat homes and businesses. The first shipment is expected to leave the Port of Baltimore next month at a cost of $113 per metric ton.

Energy Secretary Rick Perry said U.S. coal “will be a secure and reliable energy source” for Ukraine, which he said has been “reliant on and beholden to Russia to keep the heat on. That changes now.”

The U.S. “can offer Ukraine an alternative, and today we are pleased to announce that we will,” Perry said, calling such deals “crucial to the path forward to achieve energy dominance” for the U.S.

President Donald Trump has vowed to revive the struggling coal industry and has cited increases in U.S. coal exports as evidence the strategy is working. The Energy Department said in July that coal exports have risen sharply in 2017 amid increased demand in Asia and Europe, but are still below capacity.

The deal comes amid increased tensions in U.S.-Russia relations. Russian President Vladimir Putin says the U.S. will have to cut its diplomatic staff in Russia in response to new sanctions against Russia. Congress approved those because of Russian interference in the 2016 U.S. election and its military aggression in Ukraine and Syria.

Commerce Secretary Wilbur Ross said the coal deal will allow Ukraine to diversify its energy sources ahead of the coming winter, noting that Russia has restricted some natural gas deliveries to Ukraine and other neighbors in a bid to “choke off opposition to its ambitions.”

Perry was recently fooled by a pair of Russian pranksters impersonating the prime minister of Ukraine. Topics on the mid-July call included coal exports. Perry met with Ukraine’s president, Petro Poroshenko, in June.